oe des moines



- M. E. HENNING l l -April 5, 1932. RESET MECHANISM FOR YHERMAL cuT-ou'r swncrms Re. 18,409

Urgnal Filed June 16, 1930 u ,al

Reissue'd Apr. 5, 1932 UNITED STATES- MALCOLM E. HENNING, OF DES MOINES, IOWA, ASSIGNOB TO PENN ELECTRIC C0., \DES MOINES, IOWA, A CORPORATION OF IOWA uRe. 18,409

.PATENr OFFICE RESET MECHANISM FOB,l THERMAL CUT-OUT SWITCHES Original No. 1,841,477, dated JanuaryJB, 1932, Serial No. 461,546, iled June 16, 1930. Application for reissue led January 25, 1932. Serial No. 588,799.

The object of my present invention is to provide a reset mechanism for switches which have overload cutouts of current responsive type, the mechanism being simple and etlective in itsv operation.

A further object is to provide a reset mechanism for thermal cutout switches or the like which will positively prevent the possibility of manually holding the switch in closed circuit position when the current responsive cut-` and a current responsive circuit opening mechanism for the switch member, of a reset member movable to reset the current responsive mechanism and at the same time operable to retain the switch member in open circuit position whereby to prevent closure of the switch member except when the reset member is released or the current responsive means when reset is in position to allow movement of the switch member to closed circuit' position.

With these and other" objects in view, my invention consists in the construction, arrangement and combination of the various parts of my device, whereby the objects contemplated are attained, as hereinafter more fully set forth, pointed out in my claims and illustrated in the accompanying drawings. Although the .invention is susceptible of a variety of embodiments, it is unnecessary to fully describe and illustrate more than one in order to give a full' understanding-'of the invention both from'its structural and functional standpoints. Accordingly, I have illustrated a. preferred and desirable embodiment of the invention in the accompanying drawings, in which: y

Figure 1 is a perspective view`of an automatic switch structure showing it diagrammatically connected with a mechanical refrigerator.

Figure 2 is an enlarged front elevation of the switch showing. the cover removed.

Figure 3is an enlarged sectional view on the line 3-3 of Figure 2.

Figure 4 is a sectional view on the line 4-4 of Figure 3; and

Figure 5 is a diagrammatic view of the parts and electrical connections of the switch.

On the accompanying drawings, I have used the referencey numeral 10 to indicatef1 switch casing. A cover 12 is provided there The particular switch illustrated is of the automatic type for cont-rolling the'supply of electric current to a machine such as the motor 14 of a mechanical refrigerating system 16, the temperature of which controls the switch through a temperature responsive element 18 and connecting tube 20.

by variations in temperature in the element'18 will contract and expandthe bellows 24. A head-26 of the bellows-24 carries a pin 28, Whichengages one side of a primary lever 30. The lever 3() is pivoted on a pin 32'. I

A spring 34 is provided with a pin 36 con tacting with the opposite side of the primary lever 30 whereby the spring opposes the bellows 24 and balances the lever 30 between the bellows and the spring. The spring 34 is preferably adjustable. l

A switch arm 38 is pivoted on a pin 40 and operatively connected with the primary lever 30 by a link 42. A permanent magnet 44 acts 'upon the switch arm 38 to pull it rI he tube- 2O is connected with a fitting 22 which communicates with a bellows 24 where-- toward a closed circuit position in opposition to the spring 34 which tends to move the switch arm to an open circuit position. Variations in the expansion o-r contraction. of the bellows 24 will move the switch arm to open and closed positions, depending on thetemperature or pressure action upon the bellows.

A ,stationary contact plate 46 is connected vwith a contact prong 48 and carries a consisting of a cutout arm 62 and a thermal latch 64 therefor. -The cutout arm 62 is pivoted on a pin 66 and'is provided with an thermal cutout arm 62 ma extension 68 in position to engage the switch arm 38, when a spring 7 O'is allowed to. move the cutout arm 62 toward the right, as viewed in Figure 2. lThe thermal latch 64 is a strip of bimetallic met-al having one end anchored to aitting 72, which is pivoted on a screw 74. The thermal bar 64 isprovided with an openingv7 6 -into which -a latch lug 78 of the extend when the arm' 62 is in latched position. The fitting 72 is connected with a second thermal bar 80 mounted in opposition to the thermal latch V64 so .as to prevent external temperature changes from affecting the operation of `the cutout.

From the foregoing description, 1t will be obvious that when the cutout lever 62 is latched by the thermal latch 6A, the extension 68 cannot contact with the switch arm 38 and normal automaticoperation of the switch arm is had.

Whenever an overload current flows through the switch, however, it Will raise the temperature of the heating element 56 for warping the thermal latch 64 to an unlatched position wherebyv the spring 70 will cause the released arm 62 to swing to the right, as viewed in Figure 2 and the extension 68 will engage the switch arm 38 andv separate the contacts and2. Thusany damage to the motor 14 is prevented when an overload, caused by clogging of the refrigeration p'pes `orany other cause, is thrown onto the motor.

My reset mechanism consists of a-reseqt lever8`2- pivoted on the pin 66 and having on one end an ear 84 adapted to engage thel cutout -lever- 62 and on its other end an extension 86-adapted to engage the switch lever 38. A reset button 88 is engageable with i y there was danger in the use of such a vswitchthat someone, when desiring the motor to continueto operate for even a short period of the ear 84 for moving the levers 82 and 62 to reset position. A release button 90 is'provided for unlatching the bar 64 from the latch lug 7 8 of the cutout lever 62 whereby the switch may be allowed to open thev circuit by.

a manual control. y

In my co-pending application, Serial No.

448,256', filed April 29, 1930, the button se contacted directly with the cutout arm 62 and time after the thermal cutout had opened the switch, would hold the button 'in and thus v hold the circuit in c] osed position and possibly burn out the motor or cause other damagev because of' the excessive current liowin g through the circuit. y y

The main object of my present invention is to eliminate such danger and I have, therefore, provided the reset lever 82 with the lug 86 to engage the switch arm v38 and positively hold it in an' open circuit position while the L button1 88 is being held in. Thus the switch can move lagain to closed circuit position only after the reset button 88 has been released v.

and providing the latch 64 is not again moved to unlatched position by excessive current 'iowing through the heatino' element 56.

theyreal spirit and purpose of my invention,

and it is my intention to cover by myrclaims, any Vmodified formsfof structure or use of mechanical equivalents, which may be reasonaby included within their scope.

' claim as my invention: a

1. In a reset mechanism for thermal cutout switches, the combination with va switch member normally movable to open-and closed circuit positions, circuit opening means foil independently moving said switch member to open circuit positionV and a thermal latch for said means, of a reset member movable tog'. latch'said circuit opening means by means of said thermal latch, said reset lmember being'operatively lconnected with said switch l member to retain it in .open circuit osition upon such latching movement of th) member.

.2.. In a reset mechanism of the character disclosed, the combination with a-switch having a stationary contact and a movable, contact and current responsive mechanism for disengaging said movable contact from said stationary contact, of reset means for said mechanism comprising ka reset member movable to resetting position and operatively connected with the switch for retaining the same in open osition when the reset mem-` ber is so moved).

3. In a reset mechanism of the character disclosed, the combination with a switch having-a stationary contact and a movable contact and Acurrent lresponsive mechanism 'for disengaging saidmovable contact'from said stationary contact, of reset means for said mechanism comprisinga pivoted reset lever movable to resetting position and. engagee reset able with the switch for retaining thel same inv open position when moved. y

4. In a .reset mechanism ofthe character disclosed, the combination with a switch member normally movable to open and closed circuit positions and 7 current responsive mechanism toindependently move the switch member to open circuit position upon an over- ,the reset lever is so load current flowing through the circuit controlled by the switch member, of reset means for said mechanism com rising a movable reset member and means or moving the same to resetting Aposition and simultaneously therewith retaining said switch member in open circuit position.`

5. In a' reset mechanism of the character disclosed, the combination with power means, a switch member movable thereby to. open and closed circuit positions and current responsive mechanism to move the switch member to open circuit position independently of said power means upon an overload current flowing through the circuit controlled by the switchv member, of reset means for said mech-- anism comprising a reset member movable to reset position and simultaneously engageable with the switch member to retain the same in open circuit position.

6. In a reset mechanism of the character disclosed, the combination with power means, a switch member movable thereby to open and closed circuit positions and current responsive mechanism to move the switch to open circuit position independent of said power means upon an overload currentlowing through the circuit controlled by the switch member, of reset means for said mechanism comprising a reset lever pivotally mounted, and means to impart pivotal movement to said reset lever to move the same to reset position, said reset lever ,having an operative connection with said switch member to retain the same in open circuit position when the reset lever is moved to reset position. v

7. In a reset mechanism of the character disclosed, the combination with a switch member normally movable to open and closed circuit positions and current responsive mechanism to move the switch member independent of its normal movement to-'open circuit position upon an overload current flowing through tht circuit controlled by the switch member, of reset means for said mechanism and closed circuit positions and current rel y -sponsive mechanism to move the switch membei' to open circuit position independently of saidpower means upon an* overload current flowing throughthe circuit controlled by the switch member, of reset means for said mechanism comprising a reset member movable to reset position and engageable with the switch member to prevent the same moving to closed circuit position so long as s'aid reset member remains in resetting position.

10. In a reset mechanismof the character disclosed, the combination with a switch having astationary contact and a movable contact normally tending to move towards closed circuit position and current responsive mechanism for disengagingy said movable contact from said stationary contact, of reset means for said mechanism comprising a reset member movable to resetting position and operatively connected with the movable contact of the switch for preventing the movable contact from engaging the stationary contact while said resetting member remains in resetting position.

disclosed, the combination witha switch having a stationary contact and a movable contact and current responsive mechanism for disengaging lsaid movable-contact from said stationary contact,'of reset means for said mechanism comprisinga pivoted -reset lever movable to resetting position and engageable with the movable contact of the switch for preventing its engagement with the stationary contact when the reset means' is in resetting position.

, Des Moines, Iowa, January 22, 1932.

MALCQLM E. HENNING.

comprising a resetlevei pivotally mounted and means to impart pivotal movement to said reset lever to move the same to reset position, said reset lever being engageable with said switch member to retain the same in open circuit position, when'the reset lever is moved to reset position.

8. In a reset mechanismo the characterr disclosed, the combination with power means, a switch member movable thereby to open and closed circuit positions and 'current responsive mechanism to move the switch member to open circuit position independently of said power means upon an overload current flow- M ns 11. In a reset mechanism of the character I ing through the circuit controlled by theswitch member, of reset means for said -I'nechanism comprising a reset member movable to reset position and engageable with the switch v member to retain the same in open circuit polao 

